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The value of R

Discussion in 'Personal' started by S1a3t5u7r9n, May 28, 2020.

  1. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    R I am told is something to do with the rate of infection Prof Van Tamm explains that an R of 3 means 1 person infects 3 others.
    So far so good.
    Mr Hancock knows we must flatten the curve and he is proud to announce R is decreasingly.
    Does an individual person have an R value?
    Or is it an individual area that has an R value
    Or is it the central Line has an R value of 2.5
    Me Cummings must know because Durham has a lower R value than London.
    Do yo know your R value
  2. abwdSTEM

    abwdSTEM Occasional commenter

    I think that the R valve is for a population (which could be the population within an area). I don't think that each individual has an R valve.

    It would be possible to get some idea of the R valve in your area/population from the graphs showing the infection curve from different parts of the UK shown during the daily briefing.

    Here in the sunny South West we have the lowest infection curve and presumably a lower R rate then the rest of the UK.
  3. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    Thanks for that.
    Am I the only person that worries that the government on a daily basis quotes the R value and bases policy based on movements of the R value but never actually shows us how it is calculated
    We are being told they may enforce localised lock downs
    I love the South West
    But would it be right to lock down Cornwall at the same time as Somerset
  4. nomad

    nomad Star commenter

    What is R?
    The reproduction number is a way of rating a disease's ability to spread.

    It's the number of people that one infected person will pass the virus on to, on average

    Measles has one of the highest numbers in town with a reproduction number of 15 in populations without immunity. It can cause explosive outbreaks.

    The new coronavirus, known officially as Sars-CoV-2, has a reproduction number of about three, but estimates vary.

    How is R calculated?
    You cannot capture the moment people are infected; instead scientists work backwards.

    Using data - such as the number of people dying, admitted to hospital or testing positive for the virus - allows you to estimate how easily the virus is spreading.

    Generally this gives a picture of what the R number was two to three weeks ago. Regular testing of households should soon give a more timely estimate.

    Why is a number above one dangerous?
    If the reproduction number is higher than one, then the number of cases increases exponentially - it snowballs like debt on an unpaid credit card.

    But if the number is lower, the disease will eventually peter out, as not enough new people are being infected to sustain the outbreak.

  5. sbkrobson

    sbkrobson Star commenter

    Actually I think you'll find it bases policy on chummy interdependence and badly concealed narcissistic expedience.
    All of this is gift wrapped and presented as "The R Value" because it is fewer words for the public to absorb, and for the public it also has analogous lexical appeal to "The X Factor".
    It's not like they just pulled the phrase out of a hat, you know. It is based on science.
    border_walker and Doitforfree like this.
  6. florian gassmann

    florian gassmann Star commenter

  7. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    Thanks for your map
    What time were these R values captured?
    How often is it recalculated?
    Do you get an R value for a London Tube Train.
    If not why not?
  8. Wotton

    Wotton Lead commenter

    Also they are influenced by the number of people tested, usually in hospital or those who have to be tested for work, as the more tested the likely hood is that you will find more people who have the virus. Think of the people who get the virus but don't need to go to hospital and stay at home and are never tested, will they appear in the R numbers.
    OK I may be talking rubbish but who knows.
  9. Rott Weiler

    Rott Weiler Star commenter Forum guide

    Because you'd have to know the identity of everyone who travelled on the tube and then link it to all their medical histories wouldn't you? Which they can't do.
    bombaysapphire and phlogiston like this.
  10. florian gassmann

    florian gassmann Star commenter

    It's from The Sun rather than me.

    I believe they are based on data from about two weeks ago which is then projected along the curve to get an estimate for the day of publication.

    Not sure. I think The Sun has run similar maps, but I don't know if they are daily.

    No, for reasons explained by Rott Weiler.
  11. dumpty

    dumpty Star commenter

    Indeed and this is I believe the Achilles Heel - the R number today is two (maybe three) weeks old, so to speak.
  12. border_walker

    border_walker Lead commenter

    dumpty likes this.
  13. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    Surely you can develop an app for that
  14. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    The Sun newspaper ( I assume) seem quite important in delivering R values.
    Are they a Tory or Labour paper
  15. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

  16. S1a3t5u7r9n

    S1a3t5u7r9n Established commenter

    Not intending to comment all night.
    The R value is complete fiction
    Unless somebody can explain otherwise
    It is apolitical tool to use against a non understanding public
    Anybody had a barbecue tonight with friends staying in a tent?
    We are off to Barnard Castle to get our eyes tested
    Catgirl1964 likes this.
  17. burajda

    burajda Star commenter

    Depends where you are in the SW. Bristol, N Somerset, Bath, S Glos and Swindon areas are much higher than Devon, Cornwall and Dorset and numbers are not declining.
  18. Alby

    Alby New commenter

    The R value is a number, a single, or sole, number, in this case linked with Covid-19. Let us label it Rsole. This number is not constant, and can vary from place to place. For example fairly recently the Rsole number in London decreased by two and a few hours later the Rsole number in the Durham region of the North East increased by the same amount. So we see the Rsole does not have fixed values, and it can be very difficult to work out what values, or indeed value, the Rsole has. Strangely, the government seems to be unconcerned about the scale on which the Rsole lies. Tragically a large, and in essence out of control Rsole has been causing and continues to cause devastation to the country. It is vitally important that the Rsole is reined in, and ideally throttled to complete insignificance.
    Catgirl1964, mothorchid and jubilee like this.
  19. EmanuelShadrack

    EmanuelShadrack Star commenter

    I think this video explains it well. R (or actually R nought) is mentioned from 7:23.

  20. T34

    T34 Lead commenter

    Not quite.
    The simple way to estimate it would be to guess a starting value (say 3), then look at the change in death rate. If the death rate halves, so has R (3 weeks previously).
    It's a scientific tool gratefully grasped by a non-understanding government.

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